Power distribution bus with protection and alarming

#The present invention relates to power distribution units and providing power from a bus within the power distribution unit. More particularly, the present invention relates to providing protection and alarming for the bus within the power distribution unit.

#Power distribution units generally provide current to downstream devices operating at a given voltage. A bus is included in the power distribution unit and acts as a voltage node that provides the current to the devices. The current that is provided to each individual device generally falls within an acceptable range. However, one or more downstream devices may draw more current than normal due to a heavier than normal load or due to a device malfunction. For purposes of protecting both the power distribution unit and the downstream device, it is desirable to block current from the power distribution unit to the downstream device when the current drawn by the device exceeds a threshold amount.

#Limiting the current to the downstream device is often done by including a fuse in each line leading to each device from the bus. The fuse often provides an alarm voltage so that when the fuse blows due to excessive current, the alarm is triggered. However, the conventional use of fuses in power distribution busses has drawbacks when multiple lines of power are being provided by the power distribution unit because the alarm circuit of conventional power distribution units indicates that a fuse is blown but does not indicate which line is blocked due to a blown fuse. Furthermore, conventional power distribution units that are configured to operate with fuses are not configured to operate with circuit breakers on some or all lines.

#FIG. 1 is a schematic of a protection and alarming configuration employing discrete alarming with fuses.

#FIG. 2 is a schematic of a protection and alarming configuration employing discrete alarming with circuit breakers.

#FIG. 3 is a schematic of a protection and alarming configuration employing selectable alarming with fuses.

#FIG. 1 shows a protection and alarm configuration 100 for a power distribution bus 146. This configuration permits fuses to be used for protection while permitting discrete alarming for each distribution line. Several manufacturers make suitable fuses, such as the Cooper Bussman TPCDS-BUL disconnect in conjunction with the Cooper Bussman TPC series fuse. Although two individual distribution lines are shown in each of the drawings, it is to be understood that only two are shown to simplify understanding of the protection and alarm configurations and that any number of distribution lines may be applicable to the various protection and alarming configurations.

#A voltage is provided on the power distribution bus 146 to a terminal 106 of a first socket 102 and to a terminal 110 of a second socket 104. The first socket has a fuse 101 that passes current from the bus 146 to a second terminal 108 that is connected to the downstream device 148. Likewise, the second socket has a fuse 103 that passes current from the bus 146 to a second terminal 112 that is connected to the downstream device 150. The terminals 106, 108, 110, and 112 may be of various types such as permanent connections or temporary connections where the alarm configuration circuitry 100 is contained in a plug-in module. The fuses 101, 103 protect the power distribution unit and downstream devices 148, 150 by breaking the current pathway when the current is excessive to either of the devices 148, 150.

#The first socket 102 may have three alarm connections 114, 116, and 118, and the second socket 104 may have three alarm connections 120, 122, 124. However, in this embodiment only one alarm connection 116, 122 of the each socket 102, 104 is used. The alarm connection 116 connects to an alarm circuit interface 130 through a conductor 126 forming a conductive path from the first socket 102. The interface 130 may be any suitable connection, permanent or temporary, that establishes continuity between the socket 102 and an alarm circuit 134. An alarm circuit 134, as is known in the art, may generate a remote alarm signal 138, such as by triggering an internal relay (not shown), and/or may light a light emitting diode (LED) 140 to provide a visual indication as to the condition of the fuse 101.